Could Nucleobases form in the ISM? A Theoretical Study in the Hoursehead nebula

Abstract

This work presents the results of a theoretical study that analyzed the possibility of nucleobases to form in the interstellar medium, in the Horsehead nebula, which is a region considered an archetype of molecular cloud. Performing the Meudon PDR code, the reactions of the nitrogen bases formation from formamide, which is a precursor compound identified in several interstellar environment, where simulated. The model showed that at least cytosine and uracil presented significant abundances. Finally, from thermochemical and quantum calculations, a investigation was carried out on the formation reactions considered for the nucleobases and no insurmountable energy barrier which would prevent the reactions was found.